Isolation and characterization of amyloid fibril protein from various types of systemic amyloidosis and localized amyloid deposits. Mechanism of formation of amyloid deposits by lysosome enzyme digestion of immunoglobulin precursors. Isolation and purification of proteolytic enzymes involved in immunoglobulin degradation. Chemical characterization of abnormal circulating proteins in various disease states, e.g. rheumatoid arthritis.